1. Field of the Invention
The present invention relates to a light emitting diode package, and more particularly, to a side illuminating light emitting diode package having a small degree divergent angle.
2. Description of the Prior Art
In recent years, display technologies have advanced significantly, and after continuous research and development, products including liquid crystal displays (LCDs), plasma displays, and organic light emitting diode displays of various sizes have been widely utilized in various industries. Essentially, the direction of development of the display industry has been moving toward a direction of high brightness and high yield to manufacture more valuable and cost-effective products for the industry. Of all critical components of a display, the backlight module utilized for providing the light source has been recognized as one of the most important parts for determining the effectiveness of the product. Hence, a well-designed backlight module is able to effectively increase the brightness of the display and also expand the flexibility of other components during the fabrication process, whereas a poorly designed backlight module will not only provide a limited brightness but also influence the performance of the display.
Typically, the backlight module is divided into two categories: edge light and direct-underlying. However, backlight modules utilizing light emitting diode as the light source have also become increasingly popular. Essentially, a backlight module combined with light emitting diodes is able to provide advantages including high luminosity, high detail, and high coloration, without the use of mercury. Consequently, the backlight module can be applied in numerous fields including cars, displays, televisions, and portable electronic products, and when a light emitting diode is utilized as a light source, the illumination direction of the light emitting diode has to be carefully manipulated to generate an effective light source for increasing the overall brightness of the display product.
FIG. 1 is a perspective diagram showing a conventional light emitting diode package 10. As shown in FIG. 1, the light emitting diode package 10 includes a packaging substrate 12 and a light emitting diode chip 14. In general, the flow of an electrical current through the PN junction of the light emitting diode chip 14 will facilitate electrons to combine with electron holes to produce light. Since light is projected in different directions, most of the light will be collected into a ±60° divergent angle. Nevertheless, when the light emitting diode package 10 is applied to the side of a light device, the illumination intensity produced by the divergent angle 16 will become unsatisfactory.
FIG. 2 is a perspective diagram showing another conventional light emitting diode package 30. As shown in FIG. 2, the light emitting diode package 30 includes a hemispherical lens 32. When light is projected from the light emitting diode package 30, the field of illumination 34 produced will travel along the axis 36 of the light emitting diode package 30 as a result of the influence of the hemispherical lens 32. Most of the light produced by the light emitting diode package 30 is projected upward, whereas a small portion of the light is projected away from the two sides of the light emitting diode package 30.
FIG. 3 is a perspective diagram showing the light emitting diode package 30 from FIG. 2 disposed on the sideline of a light guide plate 38. As shown in FIG. 3, the light emitting diode package 30 usually functions together with a reflector 42 in order to control the direction of the light beams for achieving satisfactory illumination. Preferably, the reflector 42 functions to reflect and straighten the light produced by the hemispherical lens 32 to form a virtually parallel light 44 before entering the light guide plate 38 and after a series of optical transformations, a uniform and flat light source is produced for the display.
A nearly parallel and uniform light 44 can be produced by combining the light emitting diode package 30 with the reflector 42. However, the light has to go through a series of medium conversions and after each conversion, and a part of the light will be absorbed by the medium in the form of energy and then transform the energy to heat energy in the medium. As a result, the illumination will be greatly decreased after going through numerous medium conversions.
Therefore, it has become a popular topic for the industries to develop a new light emitting diode package that does not only have a small divergent angle, but also qualifies the need for achieving high illumination efficiency without having to go through numerous medium conversion processes.
It is therefore an objective of the present invention to provide a light emitting diode package for solving the above-mentioned problems.